The isomeric structures of(E)-1-[4-(2-hydroxy-5-methoxybenzylideneamino)-phenyl] ethanone(I) and(E)-1-[4-(2-hydroxy-4-methoxybenzylideneamino) phenyl]ethanone(Ⅱ) ,both C16H15NO3,have been determined using X-ray diffraction techniques and characterized by IR,and their molecular structures have also been optimized at the B3LYP/6-31G(d,p) level using density functional theory(DFT) . The energetic behaviors of the title compounds in solvent media have been examined using B3LYP method with the 6-31G(d,p) basis set by applying the polarizable continuum model(PCM) . The total energies of the title compounds decrease with the increasing polarity of the solvent. In addition,DFT calculations of the title compounds’ molecular electrostatic potentials(MEP) were performed at the B3LYP/6-31G(d,p) level of theory. X-ray study shows that the title compounds both have strong intramolecular O-H…N hydrogen bonds. The molecules of Ⅰ are linked into a one-dimensional framework structure by C-H…π interactions,while in Ⅱ,intermolecular π···π interactions result in the formation of infinite chains running along the [010]. The isomeric structures of (E) -1- [4- (2-hydroxy-5-methoxybenzylideneamino) -phenyl] ethanone (I) ethanone (II), both C16H15NO3, have been determined using X-ray diffraction techniques and characterized by IR, and their molecular structures have also been optimized at the B3LYP / 6-31G (d, p) level using density functional theory (DFT) . The energetic behaviors of the title compounds in solvent media have been examined using B3LYP method with the 6-31G (d, p) basis set by applying the polarizable continuum model (PCM). The total energies of the title compounds decrease with the increasing In addition, DFT calculations of the title compounds’ molecular electrostatic potentials (MEP) were performed at the B3LYP / 6-31G (d, p) level of theory. X-ray study shows that the title compounds both have both strong intramolecular OH ... N hydrogen bonds. The molecules of I are linked into a one-dimensional framework structure by CH ... π i nteractions, while in Ⅱ, intermolecular π ··· π interactions result in the formation of infinite chains running along the [010].